Sergey Biryukov

Allows to find all posts where a particular attachment (image, video, etc.) is used.
Adds a “Used In” column to the list view in Media Library, as well as to the attachment details modal.
Finds posts that use the image (including any of its intermediate sizes) in post content, or as a featured image. Works with custom post types too.
Inspired by a <a href="http://wptavern.com/the-problem-with-image-attachments-in-wordpress" rel="nofollow ugc">WP Tavern post</a> on image attachments.

Find Posts Using Attachment

Allows to find all posts where a particular attachment is used.

Ruslan Mikhno

This is a very simple plugin that allows you to bulk change author for media files.
The action is added in the “List” view of the Media Library.

Bulk Change Media Author

Bulk change author for multiple media files, using the default WP Media Library.

Find Posts Using Attachment vs Bulk Change Media Author